Abstract: A subject of the invention is a fluidized-bed reactor for producing granular polycrystalline silicon. The fluidized-bed reactor comprises a segmented reactor tube, which is disposed between a reactor top and a reactor bottom, a heating facility, at least one nozzle for supplying fluidizing gas, at least one nozzle for supplying reaction gas, a facility for supplying silicon seed particles, a product removal line, and an offgas removal line. The segmented reactor tube comprises a base segment and at least one spacer segment, there being disposed, between base segment and spacer segment, a flat seal made from a carbon-containing material, the spacer segment consisting of a material which, within a temperature range from 100 to 950° C., has a thermal conductivity of <2 W/mK.

Abstract: The fluidized bed process for preparing polysilicon by chemical vapor deposition is improved by positioning at least one Laval nozzle upstream from a gas inlet into the reactor.

Abstract: A subject of the invention is a fluidized-bed reactor for producing granular polycrystalline silicon. The fluidized-bed reactor comprises a segmented reactor tube, which is disposed between a reactor top and a reactor bottom, a heating facility, at least one nozzle for supplying fluidizing gas, at least one nozzle for supplying reaction gas, a facility for supplying silicon seed particles, a product removal line, and an offgas removal line. The segmented reactor tube comprises a base segment and at least one spacer segment, there being disposed, between base segment and spacer segment, a flat seal made from a carbon-containing material, the spacer segment consisting of a material which, within a temperature range from 100 to 950° C., has a thermal conductivity of <2 W/mK.

Abstract: Contamination of fluidized bed-produced polycrystalline granules by phosphorus is reduced by employing as seals and/or packings, graphite containing <500 ppmw of phosphorus.

Abstract: Silicon seed particles which can be used for producing polycrystalline silicon granules in a fluidized-bed reactor are prepared by a process wherein a milling gas stream is introduced into a chamber containing polycrystalline silicon granules, as a result of which individual particles of the polycrystalline silicon granules are accelerated in such a manner that they collide with other particles of the polycrystalline silicon granules, and in this manner the polycrystalline silicon granules are comminuted, wherein the milling gas stream is introduced into the chamber by at least one jet nozzle made of hard metal.

Abstract: Plastic material-comprising surfaces of a substrate are coated with elemental silicon by cold gas spraying by injecting a powder containing silicon into a gas and powder with a high velocity onto the substrate surface, such that the silicon forms a firmly adherent coat on the substrate surface comprising the plastics material. Apparatuses having such silicon-coated surfaces are useful in minimizing contamination of polycrystalline silicon production, processing, packaging, and transport.

Abstract: Control of the flow of granular polysilicon granules is effected by employing an elastomeric pinch sleeve valve. The flow control by this method is especially useful for controlling the flow of silicon seed particles and granular polysilicon product in the fluidized bed method for producing polysilicon. The flow may be stopped without gas leakage, and is suitable for use over long operating campaigns.

Abstract: Assembly of a fluidized bed reactor for the preparation of polycrystalline silicon granules by chemical vapor deposition of silicon onto seed particles and removal of polycrystalline silicon granules is facilitated without breakage and with gas tightness by a specific assembly sequence.

Abstract: Control of the flow of granular polysilicon granules is effected by employing an elastomeric pinch sleeve valve. The flow control by this method is especially useful for controlling the flow of silicon seed particles and granular polysilicon product in the fluidized bed method for producing polysilicon. The flow may be stopped without gas leakage, and is suitable for use over long operating campaigns.

Abstract: Assembly of a fluidized bed reactor for the preparation of polycrystalline silicon granules by chemical vapor deposition of silicon onto seed particles and removal of polycrystalline silicon granules is facilitated without breakage and with gas tightness by a specific assembly sequence.

Abstract: Contamination of fluidized bed-produced polycrystalline granules by phosphorus is reduced by employing as seals and/or packings, graphite containing <500 ppmw of phosphorus.

Abstract: Plastic material-comprising surfaces of a substrate are coated with elemental silicon by cold gas spraying by injecting a powder containing silicon into a gas and powder with a high velocity onto the substrate surface, such that the silicon forms a firmly adherent coat on the substrate surface comprising the plastics material. Apparatuses having such silicon-coated surfaces are useful in minimizing contamination of polycrystalline silicon production, processing, packaging, and transport.

Abstract: A fluidized-bed reactor for preparing granular polycrystalline silicon has a reactor vessel, a reactor tube and a reactor bottom within the reactor vessel, and an intermediate jacket located between the reactor tube and the reactor vessel, a heating device, at least one bottom gas nozzle for introducing of fluidizing gas and at least one secondary gas nozzle for introducing reaction gas, a silicon seed particle feed, an offtake line for granular polycrystalline silicon and reactor offgas discharge, wherein a main element of the reactor tube comprises at least 60% by weight of silicon carbide with a CVD coating having a layer thickness of at least 5 ?m and is at least 99.995% by weight of SiC, or a main element of the reactor tube is a sapphire glass comprising at least 99.99% by weight of ?-Al2O3.

Abstract: Silicon seed particles which can be used for producing polycrystalline silicon granules in a fluidized-bed reactor are prepared by a process wherein a milling gas stream is introduced into a chamber containing polycrystalline silicon granules, as a result of which individual particles of the polycrystalline silicon granules are accelerated in such a manner that they collide with other particles of the polycrystalline silicon granules, and in this manner the polycrystalline silicon granules are comminuted, wherein the milling gas stream is introduced into the chamber by at least one jet nozzle made of hard metal.

Abstract: The fluidized bed process for preparing polysilicon by chemical vapor deposition is improved by positioning at least one Laval nozzle upstream from a gas inlet into the reactor.

Abstract: Silicon granules are conveyed in an encapsulated conveying channel by swaying movement of the channel produced by a permanent magnet excited by an external alternating electromagnetic field.

Abstract: Silicon granules are conveyed in an encapsulated conveying channel by swaying movement of the channel produced by a permanent magnet excited by an external alternating electromagnetic field.